A computational and experimental investigation on thermal conductivity of particle reinforced epoxy composites

The finite element method (FEM) is a powerful computational technique for approximate solutions to a variety of “real-world” engineering problems having complex domains subjected to general boundary conditions. In this paper FEM is implemented to determine the effective thermal conductivity of particulate filled polymer composites and is validated by experimentation. A commercially available finite-element package ANSYS is used to for this numerical analysis. Three-dimensional spheres-in-cube lattice array models are constructed to simulate the microstructure of composite materials for various filler concentrations ranging from about 6 to 36 vol.%. Composites with similar filler contents are fabricated by hand layup technique by reinforcing micro-sized pine wood dust in epoxy resin. Guarded heat flow meter test method is used to measure the thermal conductivity of these composites using the instrument Unitherm™ Model 2022 as per ASTM-E1530. This study shows that the incorporation of pine wood dust results in reduction of conductivity of epoxy resin and thereby improves its thermal insulation capability. With addition of 6.5 vol.% of filler, the thermal conductivity of epoxy is found to decrease by about 19.8% and with about 36 vol.% of filler addition, a 57.3% reduction in thermal conductivity of neat epoxy is achieved. The experimentally measured conductivity values are compared with the numerically calculated ones and also with the existing theoretical and empirical models. The values obtained using finite-element analysis (FEA) are found to be in reasonable agreement with the experimental values.